the pagespeed test is done user-side, and those images are popping up fine over here. Perhaps you are experiencing some lag with your ISP... At least over here, I am getting anything between 50 and 100 milliseconds for the image to show.
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uberconversionMay 16 '13 at 10:37

Please do various checks using webpagetest.org using multiple servers near to the location of your server location... Use 20mbit connection, and report back your findings.. Provide the test URLS that they produce.
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Simon Hayter♦May 16 '13 at 11:18